There are numerous fuel supply and carburetor linkage control mechanisms all of which are intended to control the position of a throttle to effect an appropriate engine idle speed. Idle speed controls operable by solenoid operated devices have been widely proposed. In still other engine idle speed controls, control means have been adapted to operate from an output signal derived from an input signal which represents a given engine speed, thereby accomplishing a feedback control of engine idling speed. In still other throttle positioning devices, various diaphragm means have been used to establish a throttle position. These expedients, the usage of feedback control signals, have achieved various degrees of success. But the basic approaches of these various prior art devices is discarded in the present invention in favor of a latching mechanism wherein a latching device develops a defined extended position for a throttle control. This defined position is intended to define specific idle positions of the throttle.